Paramyxoviruses

Question 1

Structure ?

Answer 1

(-) ssRNA
enveloped
8 proteins
G-glycoprotein surface protein for attachment and entry
M-matrix protein for linking

Question 2

Pathogenesis ?

Answer 2

replicates in epithelial cells of ciliated airways
cytokine and chemokine release –> airway inflammation
secondary infections predisposed

Question 3

Transmission ?

Answer 3

droplet transmission (aerosol and fomites), need close contact

Question 4

Immunity ?

Answer 4

humoral (maternal derived antibodies)
cellular (CD8+ T-cells)

Question 5

What is the most important pneumoviruses ?

Answer 5

Bovine Respiratory Syncytial Virus (BRSV)

Question 6

BRSV overview

Answer 6

cows predisposed by stress
inflammation of the resp epithelium
CS : pyrexia, cough, nasolacrimal discharge, dyspnoea, emphysema
vaccines give poor protection.

Question 7

Diagnosis ?

Answer 7

blood rise in antibody titre and nasal aspirates
virus isolation
immunofluorescence
PCR
swabs from resp tract

Question 8

Avian Metapneumoviruses overview

Answer 8

recently discovered
URT disease (infects epithelial cells)
CS : resp signs, egg drop, swollen head syndrome
live vaccines and inactivated vaccine 4-6w later

Question 9

Name the most important respiroviruses

Answer 9

Bovine Parainfluenza Virus Type 3 (PIV3)
Canine PIV5

Question 10

PIV3 overview

Answer 10

inflammatory disease of cows in absence of secondary infection
causes enzootic pneumonia
CS : pyrexia, cough, nasolacrimal discharge, resp signs

Question 11

canine PIV5 overview

Answer 11

associated with kennel cough !!
self-limiting, only causes serious disease if combined with secondary infections
CS : characteristic cough (paroxysms of hard dry coughing plus retching and gagging)
live attenuated vaccine

Question 12

Name the most important Morbilliviruses

Answer 12

Rinderpest virus
Pest des Petits Ruminants Virus (PPRV)
Canine Distemper

Question 13

Rinderpest overview

Answer 13

most feared animal plague known to man
now eradicated !
CS : mucopurulent ocular and nasal discharges, excoriation of perineum and tail
disease of the 3 Ds = discharge, diarrhoea and death

Question 14

PPRV overview

Answer 14

“goat plague”
infects macrophages and monocytes, travelling to lymph tissues to replicate and them systemically disseminating to LNs, spleen and Peyer’s patches
CS : acute pneumonia and severe gastroenteritis
live attenuated vaccine available

Question 15

Canine distemper overview

Answer 15

within 3-6 days, virus replicates in lymph tissue, leading to immune suppression and fever
also see viremia
CS : resp signs, GI signs, acute and chronic progressive neuro signs, hyperkeratosis (“hard pad”), epileptic seizures and excessive chewing movements with salivation

Question 16

Name the most important Avulaviruses

Answer 16

Newcastle Disease Virus

Question 17

Newcastle Disease overview

Answer 17

lentogenic form - low virulence
mesogenic form - moderate virulence
velogenic form - highly virulent, causes severe disease and high mortality
CS : resp signs, oedema of the face, greenish diarrhoea, neuro signs
vaccines availble